134 
THE OCEAN WORLD. 
secondary system of net-work, wlncli brings them into diiect commu 
nication with the polypes. The alimentary fluids elaborated by the 
polypes pass into the branches of the secondary and irregular net- 
work system, in order to reach the great parallel tubes which extend 
from one extremity of the organism to the other, serving the same 
purpose to the whole community. 
When the extremity of a branch of living coral is tom or broken, a 
white liquid immediately flows from the wound, which mingles with 
water, and presents all the appearance of milk. This is the fluid 
aliment which has escaped trom the vessel containing it, charged with 
the debris of the organism. 
What occurs when the bud produces new polypes ? It is only 
round well-developed animals, and particularly those with branching 
extremities, in which this phenomenon is produced. The new beings 
resemble little white points pierced with a central orifice. Aided by 
the microscope, we discover that this white point is starred with ladia- 
ting white lines, the edge of the orifice bearing eight distinctly traced 
indentations. All these organs are enlarged step by step until the young- 
animal has attained the shrub-like or branched aspect which belongs 
to the compound polype. The tube is branching, and the orifices from 
which the polypes expand become dilated into cup-like cells. 
The coral of commerce, so beautiful and so appreciated by lovers ot 
bijouterie, is the polypier. It is cylin- 
drical, much channeled on the sur- 
face, the lines usually parallel to the 
axis of the cylinder, the depressions 
sometimes corresponding to the body 
of the animal. If the transverse 
section of a polypier be examined, it 
is found to be regularly festooned 
on its circumference. Towards its 
centre certain sinuosities appear, 
sometimes crossing, sometimes tri- 
gonal, sometimes in irregular lines, 
and in the remaining mass are red- 
J/Ul. ‘i 
Fig. 53. 
Section of a Branch of Coral. 
(Lacaze-Outhiers.) 
dish folds alternating with brighter 
spaces which radiate from the centre towards the circumference (Pig. 53). 
In the section of a very red coral, it will be observed that the colour 
